


fill me with your love

by a_splash_of_stucky



Series: happy 100th birthday steebie [4]
Category: Captain America (Movies), Marvel Cinematic Universe
Genre: Alpha Steve Rogers, Alpha/Beta/Omega Dynamics, Alternate Universe - No Powers, Anal Fingering, Anal Sex, Blowjobs, Bottom Bucky Barnes, Breeding, Breeding Kink, Bucky still has his metal arm tho, Explicit Sexual Content, Fingering, M/M, Mating Cycles/In Heat, Omega Bucky Barnes, Oral Sex, Post-Serum Steve Rogers, Rutting, Top Steve Rogers, unprotected sex
Language: English
Status: Completed
Published: 2018-07-04
Updated: 2018-07-04
Packaged: 2019-06-05 01:37:57
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 5,103
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/15159563
Author URL: https://archiveofourown.org/users/a_splash_of_stucky/pseuds/a_splash_of_stucky
Summary: When Steve's rut hits, he and Bucky have some pretty fantastic sex.





	fill me with your love

**Author's Note:**

> Fill for my MCU KB square - A/B/O: rut sex
> 
> It’s here! I’ve been so excited to post this one, but I wanted to save it for a special occasion – and what’s more special than Steve’s 100th? To all you kinky little fuckers that love some a/b/o Stucky, this one’s for you.
> 
> Also, as I was writing this, I kinda-sorta rediscovered my breeding kink, and I might have gone a little OTT with it. Thus, **breeding/thoughts of breeding/implied mpreg** feature heavily in this fic. If that’s not your thing, then STOP READING NOW.

Unlike most Alphas, Steve does not have a regular, predictable rut cycle. He’d had a couple of ruts when he was a teenager, but they’d been pretty weak, as his frail body was unable to cope with anything stronger. After his surgery and hormone treatment, he’d put on weight and got sick less frequently, but his irregular ruts had remained. His doctors had tried all sorts of things to address the issue, but Steve’s resigned himself to the fact that his ruts will come whenever they please.

With that being said, Steve can always tell when his rut is due. His pre-rut symptoms are a right bitch, worse than what most other Alphas have to go through. He’s got the usual behavioural changes – heightened stubbornness, irritability, increased desire to fight – and on top of that, his body aches like he’s just been run over by a tank. There’s a permanent itchiness under his skin, one that won’t go away no matter what he does. His appetite increases tenfold. It becomes so much harder to resist following the logic of his hindbrain, to think beyond satisfying his basal needs of eating, sleeping and fucking.

Luckily, his pre-rut symptoms only last for about a week.

Bucky  _hates_ Steve when he’s in pre-rut. Or, well. Bucky hates Steve as much as he  _can_ hate Steve, which is not that much, really. It’s more of an increased annoyance.

When he’s in pre-rut, Steve has a tendency to coddle Bucky. He’s ridiculously overprotective, reluctant to let Bucky leave his sight. Sure, Bucky likes being doted on once in a while, but Steve lays it on especially thick during this time, making it hard to stomach. Bucky hates feeling like he’s being suffocated. Steve’s behaviour drives Bucky crazy, and he wishes that he could control himself better.

Hence, it’s a relief to Steve when he wakes up one morning to find that he has transitioned into full-rut overnight. The itchiness under his skin has taken on a new intensity, like fire ants are crawling through his veins. There’s a mild throbbing in his groin and an ache in his jaw; he wants to fuck, to bite, to claim.

He stretches out his arms and frowns when he finds Bucky’s side of the bed to be empty; the sheets are still slightly warm to the touch.

Steve rolls onto his right side and glances at the clock on his bedside table. If this were a normal day, then Bucky would be at work by now, but he’d called in yesterday to tell his boss that he was taking the rest of the week off for partner support. All mated Alphas and Omegas are allocated a certain number of days of leave per year, in order to help their partner through a rut or heat cycle.

As Bucky and Steve have been mated for a few years, Steve’s ruts will often sync up to Bucky’s heats. Bucky’s heats are regular and planned, managed by the various suppressants and hormone pills that he takes. However, Steve’s been doing a lot of travelling for work, lately, and the constantly changing time zones have thrown his body out of whack.

With a grunt, Steve heaves himself off the bed and heads to the bathroom to relieve himself, wash his face and brush his teeth. He pulls on a pair of boxers before trudging to the kitchen, where he finds Bucky at the stove, cooking up some eggs. Bucky’s shirtless and wearing a pair of loose sweatpants that ride low on his waist, the fabric clinging to the swell of his ass. His hair is pulled into a messy bun at the nape of his neck.

Steve is overcome with the urge to kiss that neck, so he plasters himself to Bucky’s back, snaking his arms around Bucky’s waist and crossing his wrists over his belly. He presses his nose to Bucky’s scent glands, inhaling the comforting and familiar smell of apple orchards and Coney Island in the summer. Bucky chuckles fondly, one hand coming to rest over Steve’s.

“Mornin’ honey,” he says, turning to press a kiss to Steve’s forehead. Steve can feel Bucky’s nostrils flaring as he scents his mate. “It’s here?”

Steve hums in agreement. “Come to bed,” he urges, lips peppering soft, butterfly kisses along the curve of Bucky’s neck. Breathing in the scent of his Omega – his  _mate –_  has loosened Steve’s grip on his self-restraint. His cock is hardening in his boxers, pressing against Bucky’s ass.

“Breakfast first, then—,”

“No,” Steve interrupts, fitting his mouth over Bucky’s scent glands and sucking hard. Bucky shivers in his grip, inhaling sharply in response. He tips his head forward, giving Steve more room to bite and suck at his neck.

“Okay, then,” Bucky murmurs agreeably. With shaky hands, he shuts off the stove and drags the pan onto the counter, abandoning the half-scrambled eggs. Steve rumbles in approval as Bucky turns in his grip, plastering their chests together.

Bucky’s flesh hand cards through Steve’s hair whilst his metal hand curls around his neck. The cool metal is a soothing balm on Steve’s heated skin. Steve kisses Bucky with unrestrained passion, tongue pressing insistently against Bucky’s lips until they part for him. His hands are roaming over Bucky’s back, whilst Bucky uses his grip on Steve to pull their bodies even closer. When Steve slides his hands down to grab two large handfuls of Bucky’s ass, his Omega moans in approval.

Steve’s nostrils flare as Bucky’s crisp apple scent takes on a caramel-sweet note, indicating his growing arousal. Their combined scents envelop Steve’s brain like a cloud, permeating every corner of his mind. His grip on his self-control slips even further as the Alpha inside him bays and howls, desperate to break free. S

“Smell so good, Buck,” Steve murmurs, his voice low and gravelly.

His lips track a path from the corner of Bucky’s mouth, over his jaw, and down his throat. He noses at the side of Bucky’s neck, chasing the source of that heady, sweet smell. His right hand slips into the waistband of Bucky’s sweats, fingertips brushing the top of his crack. Bucky gets up on his toes, allowing Steve’s fingers to travel further south, until they’re swirling in the liquid that has begun to seep out of Bucky’s hole. Steve can feel the hard line of Bucky’s cock pressing against his hip.

“Steve,” Bucky breathes, hips wiggling pointedly.

“Gonna get wet for me, gorgeous?” Steve asks, nipping on Bucky’s earlobe playfully. Bucky whines in response.

“Bedroom,” Bucky says, tugging sharply on Steve’s hair to make sure his point gets across. Pinpricks of pain dance over Steve’s scalp, making him moan softly.

“Yeah, yes,” Steve agrees, nodding in agreement. Bedroom means going back to their nest, and nesting means fucking, an activity which Steve’s dick wholeheartedly supports.

As their lips slot together like two pieces of a puzzle, Steve walks backwards and drags Bucky through the house. His fingers continue to tease Bucky’s hole and crack, coaxing yet more slick out of his Omega’s body. The smell of Bucky’s arousal is stronger now, a fog that wraps around them and mingles with the sharp tang of Steve’s rut. Steve’s nostrils flare as he scents the air. His hindbrain is rumbling in approval; their nest smells like  _them_.

When he feels the edge of the mattress against the backs of his knees, Steve turns around and dumps Bucky onto their bed. Bucky yelps in surprise, landing on their covers with a muffled  _oof_.

He looks beautiful like this, Steve thinks dazedly. Strands of hair have come loose from his bun, and the early morning light is glinting off his metal arm. His nipples are peaked and there is a rosy flush spreading over his skin. Steve’s eyes are drawn to the tent in the front of Bucky’s sweatpants, where a little wet spot is already beginning to form. The sight reminds Steve of his own need, of the rut simmering under his skin.

They’re both wearing too much.

Steve unceremoniously pushes his boxers off his legs, before grabbing hold Bucky’s sweatpants and yanking them down. Bucky laughs breathlessly as he is dragged to the foot of the bed by the force of Steve’s pulling. The offending garment gets chucked into a corner of the room. When Steve turns his attention back to Bucky, he groans heatedly. Bucky’s leaning back on his elbows, right foot on the floor, left leg splayed out over the rumpled sheets. His little cock is hard and flushed, resting against his belly. A rush of dizziness runs through Steve’s head when he realises that this stunning Omega is completely and utterly  _his_ , ripe for the taking; the bonding mark on the side of Bucky’s neck is proof of that fact.

Instinctively, Steve drops to his knees between Bucky’s legs. He curls his hands around Bucky’s thighs and starts to suck wet, noisy kisses along the toned muscles. Bucky whimpers, flesh hand flying down to tangle through Steve’s hair. Trails of slick are glistening on Bucky’s skin; Steve follows their paths with the tip of his tongue, lapping up Bucky’s heavenly taste. He closes his eyes and continues to nip and suck along Bucky’s leg, inching closer to the point where Bucky’s honey-sweet scent is strongest. As Steve nears his leaking hole, Bucky’s whines take on a hint of desperation, and his hips start rocking restlessly.

Steve slides his hands to the crease of Bucky’s thighs, resting his thumbs on either side of Bucky’s hole. He presses his thumbs into Bucky’s skin and spreads them apart, exposing Bucky’s sopping wet hole to his hungry gaze. Steve growls, cock throbbing at the sight. The furl of muscle is a blushing pink, puffy and leaking with slick; Bucky’s body is responding to Steve’s rut and the pheromones being pumped into the air. His Omega whines and squirms, perhaps embarrassed that Steve staring at his most intimate place, one that no other Alpha has had ever touched.

Steve’s cock pulses in anticipation as he imagines what it’ll be like to slide his aching length into Bucky, to spear open that sweet little hole. He knows that Bucky’s body will be hot and tight and wet, his channel gripping Steve’s shaft like a glove. Steve imagines how good it’ll feel to finally have the pressure of Bucky’s lock pressing tight around his knot, how that will calm the raging fire in his groin.

“So wet for me, Buck,” Steve says wondrously, rubbing one thumb over Bucky’s slick hole, awed by the way the muscle twitches and flutters at his touch.

“ _Steve_ ,” Bucky whines, the unmistakeable sound of an Omega in need.  _His_  Omega.

Steve hushes him, petting Bucky’s sweaty skin with his fingers. “S’okay, Buck. M’gonna take care’a you.”

Saliva is pooling in Steve’s mouth; he needs to taste his mate. He bends his neck, closes his lips over Bucky’s dripping hole and sucks  _hard_. Bucky cries out in surprise, feet kicking out as his fingers tighten their grip on Steve’s hair. His thighs twitch as he reflexively tries to close them, but Steve’s broad shoulders prevent him from doing so. Steve moans happily as Bucky’s scent soars, that caramel-like sweetness becoming even richer.

Bucky uses his hand to hold Steve’s head in place as he grinds his ass into Steve’s mouth. Steve works his tongue into Bucky’s hole, flicking and teasing the tip of his tongue around Bucky’s rim, encouraging the furl of muscle to loosen up. Bucky’s slick floods his mouth and coats his tongue, overwhelming his senses with the taste of Bucky’s arousal. Steve feels intoxicated, drunk on Bucky’s taste and high on his scent.

He pulls back with a heaving gasp, watching as Bucky’s hole trembles and flutters from the sudden loss of stimulation. Bucky mewls and squirms, greedily trying to seek out more. His movements stop when Steve growls in warning.

Steve bends forward again, this time tracing the flat of his tongue over Bucky’s balls, which are pulled tight to his body. Bucky keens, legs twitching in surprise and hips jerking involuntarily. Steve takes first one, then the other into his mouth, sucking on them gently and swirling his tongue over the delicate skin. Bucky moans brokenly when Steve flicks his tongue over the seam between them.

He hunches in closer and laps at the head of Bucky’s cock. Bucky shouts, his feet flailing around and hitting Steve’s ribs. The head of Bucky’s dick is leaking profusely; a pool of pre-come has puddled on his belly. Steve uses one hand to grasp the base of Bucky’s cock, holding it steady as he swallows it down to the hilt. Male omegas tend to have smaller dicks, so it’s no trouble for Steve to take Bucky all the way down in one go – his lack of a gag reflex makes his task much easier.

Bucky spasms in his grip, muscles rippling like he’s been electrocuted. He moans wantonly when Steve hums around his cock. Noises of pleasure continuously pour out of Bucky’s mouth as Steve bobs his head up and down Bucky’s length. The plates in his metal arm whirr and click restlessly, like they’re responding to the stimuli too. Steve keeps his lips tight around Bucky’s dick, creating what he has learned to be the perfect amount of suction for his Omega. Every now and then, Steve uses his tongue to flick at the underside of Bucky’s cock, revelling in the way Bucky’s breathing hitches each time.

Steve uses his right hand to fondle Bucky’s balls, rolling them between his thumb and forefinger, causing Bucky to yell out a curse. His hand travels lower, sliding through the slick gathering in the crease of Bucky’s ass. With his fingers coated in Bucky’s arousal, Steve finds it easy to slide two into Bucky’s body. His Omega shouts, hips bucking into Steve’s mouth and consequently shoving his cock down Steve’s throat. Steve moans his approval.

He’s dizzy, overwhelmed by the scent and taste of his Omega. It wraps around him completely, like an all-encompassing blanket, stoking the fire of his rut. He’ll need to take care of that soon, as his knot is itching to pop, but Steve needs to prepare Bucky’s body a little more before he can bury his cock inside him.

Steve curls his fingers inside Bucky’s channel, marvelling at how tightly the muscles grip his fingers. His motions are perfunctory, but not hurried – he wants to open Bucky up so that Bucky can take his cock, but he doesn’t want to spend any more time doing this than necessary. On any other day, he’d try to make Bucky come from his fingers and his mouth alone, but he can’t indulge that fantasy right now; his rut-brain has other plans.

Bucky sobs in pleasure as Steve spreads his fingers apart, twisting his wrist to loosen Bucky’s walls. Slick pours out of Bucky’s body in a steady stream, coating Steve’s hand and wrist. When Bucky is relaxed enough to take another, Steve presses in with three fingers, working them in slowly so that Bucky has time to get used to the stretch. He’s purposefully avoiding Bucky’s prostate, as he doesn’t want Bucky to come until Steve can get his cock inside him.

“Stevie, Steve—Alpha,  _oh_ ,” Bucky moans, fingers flexing and twitching in Steve’s hair. His hips are undulating restlessly, torn between thrusting his cock into Steve’s mouth and shoving his ass onto Steve’s fingers.

“Alpha,” Bucky whines, “Alpha –  _please_ , p-please, I—I’m gonna come— _no_!”

Bucky whines pitifully as Steve rips his fingers and mouth away before he can tip over the edge. Steve wipes his mouth with the back of his left hand as he eyes his Omega. Bucky’s chest is heaving with exertion, and a rosy flush has spread across his skin. His hair is matted and sweaty, clinging to his temples and the side of his neck.

Steve’s cock – which has thus far been neglected – is now demanding attention. It’s achingly hard, the tip an angry red. His groin pulses with need. The loose skin in the middle of his shaft where his knot will form feels like it’s on fire, eager to be buried in his Omega’s tight hole. Alpha’s knots are positioned in the middle of their shafts, giving them some ability to thrust once they’ve tied with an Omega. Locked in an Omega’s channel, Alphas can generate enough friction to stimulate themselves to orgasm. Steve is lightheaded with his need to bury his knot inside Bucky’s hot, welcoming body.

Bucky sniffles and whimpers as Steve kisses his way up his body, still recovering from the orgasm that he’d been denied. Steve crawls up the bed like a predator, a permanent Alpha growl vibrating in the back of his throat. Bucky closes his eyes and tips his head back, baring his neck in submission. Steve’s arousal soars. He grabs hold of Bucky’s biceps and manhandles him up the bed.

“Alpha,” Bucky purrs, a gentle smile on his lips as he runs his hands over Steve’s shoulders. Steve rumbles in response, nosing at the crook of Bucky’s neck, where a scent gland is located.

“Want you so bad, gorgeous,” Steve husks. Bucky hums in response as his thighs hook around Steve’s waist, pulling him close.

“Then take me, Alpha,” Bucky whispers, nipping at the side of Steve’s jaw cheekily.

Steve groans in response, spreading his knees apart so that Bucky’s thighs are forced even wider, exposing his sloppy, wet hole to Steve. Bucky winds his arms around Steve’s neck and presses their foreheads together, making soft, needy, encouraging whines all the while. Steve’s desire is blinding him, making his hand tremble as he takes himself in hand. He jerks his cock a couple of times, using the slick that coats his right hand to lube up his dick – even that brief touch is almost enough to make him shoot off. Steve closes his eyes and takes a shuddery breath as he guides his dick to Bucky’s waiting entrance.

They groan in tandem as Steve breaches Bucky’s hole. There’s a moment of resistance before the head pops past the ring of muscle, into the waiting heat of Bucky’s body. Steve’s hindbrain is growling its approval, happy that his cock is finally inside his Omega, making Bucky undeniably his. Steve pushes in slowly but never gives Bucky time to adjust, stopping only when his balls are pressed flushed to Bucky’s ass.

Bucky wails at the sudden fullness, fingers scrabbling for purchase on Steve’s sweaty skin. Steve hushes him, hunkering close as he noses and scents at Bucky’s neck. His lips are parted, warm breath fanning over Bucky’s skin as he mouths wet kisses over Bucky’s glands. A soft rumble starts up in his chest to placate his slightly distressed Omega.

Once Bucky has settled, Steve presses a kiss to his temple as he starts to draw his hips back. He keeps going until only the tip of his cock is still lodged inside Bucky’s body. When he thrusts forward again, he goes faster this time, focusing on the slick glide and tight heat gripping his shaft. Steve groans when he bottoms out, eyelids fluttering from the pleasure.

“Alpha,” Bucky whimpers breathlessly, fisting the sheets above his head. “Steve—please.”

“So good, Buck,” Steve mumbles, as his hips pull back. “So fuckin’ good.”

He sets up a slow but purposeful pace, making Bucky feel every inch of his cock as he pushes it in and drags it out. Bucky whines and thrashes in his arms, pleading for Steve to go faster, but Steve pays him no heed. His focus has narrowed down to his need to force his knot and lock them together, ensuring that his perfect Omega can’t escape. He needs to make this sweet, sweet Omega  _his._

Steve’s hindbrain is telling him to go harder, to fuck and claim and  _take_  his mate like his rut wants him to, but he is hell-bent on making this last. Once they’ve tied, he won’t be able to move like this for a long while, so they’ve got to make the most of his mobility.

The smell of their coupling is a thick fog that hangs in their bedroom. The deep, musky tang of Steve’s rut is laced with the sweeter, lighter notes of Bucky’s sweat and slick. The scent fills Steve’s nostrils, stoking the coals of arousal in his gut. His ears are filled with Bucky’s cries of pleasure. Steve is relentless in his movements, pounding into his Omega, their bodies colliding over and over again. He relishes the wet, lewd squelch he makes with each thrust, as it is the undeniable sound of their mating. Bucky’s slick continues to seep out of his hole, coating Steve’s balls, groin and thighs.

Steve widens his knees and drops his weight down, changing the angle of his hips so that the head of his cock drags over Bucky’s prostate with every thrust. Bucky cries out, the plates of his metal arm clacking constantly, overwhelmed by the onslaught of sensations. The fingers of his flesh hand dig into Steve’s shoulder, his nails leaving red welts in their wake.

“Gonna knot you, pretty,” Steve gasps. His rhythm starts to pick up, and his burst of energy pushes Bucky’s body up the bed. Bucky whines in response, teeth gnashing together.

“You gonna come for me, Buck?” Steve rasps, as he grazes his teeth over Bucky’s jaw. “Gon’ come all over my cock, show your Alpha how good it feels?”

“St-eve,” Bucky gasps brokenly, twisting his head for a kiss. Steve obliges his request, their lips crushing together in an uncoordinated symphony of teeth and tongues.

Bucky moans into Steve’s mouth as he slams his pelvis into Bucky’s ass, nailing his prostate repeatedly. Bucky’s cock is trapped between their bellies, smearing pre-come all over Steve’s abs. He keeps their bodies pressed close together so as to give Bucky the friction he needs.

“That’s it, pretty,” Steve grunts, as Bucky’s breathing starts to quicken, as his body starts to tremble. “Jus’ let go for me, c’mon, I know you’re there.”

“Steve—Alpha,  _oh_ , Alpha,” Bucky pants, “Please— _there_ , oh fuck, don’t stop—right there,  _please_.”

“Come for me, Bucky,” Steve says, a hint of growl to his voice.

“Alpha,” Bucky babbles, “Alpha, Alpha, m’gonna come, please—m’gonna, oh, oh— _oh_!”

Bucky comes with a little shout, turning his head to latch his teeth onto the hollow of Steve’s throat. Steve growls as Bucky’s channel ripples and clenches around his cock, heightening Steve’s own pleasure. Bucky’s warmth spurts warm and wet between their bodies, ribbons of come shooting out of his dick. The heady, yet sharp scent of his release fills Steve’s nostrils.

“Buck,” Steve gasps, as the pressure in his cock starts to accumulate rapidly. “Oh— _Christ_ , m’gonna— _now_ , please, I—,”

Bucky nods helplessly, understanding what Steve needs but unable to answer, still caught in the throes of his own orgasm. Steve moans heatedly, tightening his grip around Bucky as his knot starts to swell.

“Buck—Bucky,  _yes,_ that’s it, just take it sweet thing, just take it,” Steve hisses, teeth tightly clenched. “ _Fuck—_ oh, yes, yes,  _yes_.”

Steve’s vision blurs as his knot swells up, the skin in the middle of his cock going taut. When his knot pops into place, Steve grunts. Bucky whines at the pressure and sudden fullness, feet flexing and kicking at Steve’s calves. He’s breathing hard and fast, breathless from both his orgasm and the fat, unforgiving stretch of Steve’s knot. Steve groans as his hips are forced to slow down to a dirty grind, the knot making it impossible for him to pull out and thrust properly.

The pressure of Bucky’s lock around his knot is exquisite, making him dizzy and lightheaded, unable to catch his breath. No matter how many times they’ve done this, the initial feeling of tying with his Omega never loses its wonder. Now, with Steve at the height of his rut, Bucky’s tight lock satiates the fierce hunger deep within his bones. They’ll stay tied together until Steve has exhausted himself. His rut-brain is purring contentedly, happy that his knot is buried deep inside his perfect Omega.

Bucky is starting to come down from his high, weak spurts of liquid dribbling out of his cock as his orgasm wanes. His teeth are no longer biting down on Steve’s throat, but his lips are still pressed to Steve’s skin, drinking in the tang of Steve’s musky scent. Steve nuzzles Bucky’s temple, a low rumble starting up in his chest. Bucky responds with a satisfied, satiated whine.

“Okay?” Steve asks, pressing a kiss to Bucky’s cheek. Bucky nods tiredly.

There’s a painful pressure in Steve’s balls. Though his knot has popped into place, he hasn’t come, and Steve’s body is not happy about that. His cock is starting to ache, needing more friction and stimulation in order to find release. He buries his nose into the crook of Bucky’s neck and snaps his hips forward, as far as the knot allows. A part of Steve wants to give his mate a break and a chance to recover, but it hurts too much to stop.

“Alpha,” Bucky says breathily, head lolling to the side submissively, in a silent invitation.

“I know, gorgeous,” Steve says, voice strained. He closes his lips around the scent gland at the base of Bucky’s neck, thrashing his teeth and tongue over the abused skin. Bucky twitches, whining quietly.

“Gonna breed you, pretty thing, gonna fill you with my pups,” Steve says, as hips grind and roll into Bucky, his pelvic bone pressed flush to his ass. His knot is right against Bucky’s prostate, creating a never-ending wave of pleasure for his Omega. Bucky’s whimpers have increased in volume, and his body squirms in Steve’s grip, trying to get away from the unrelenting pleasure.

“Takin’ me so good, sweetheart,” Steve groans, flicking his tongue over Bucky’s collarbone.

Bucky throws his head back, exposing his kiss-bitten neck and the bonding mark on the side of his throat. The ridged scar is a perfect imprint of Steve’s teeth. Steve growls as he leans down, fitting his mouth over the mark – not biting, just grazing his teeth over the skin.

“Alpha,” Bucky moans, a shiver running through his overstimulated body.

“Gonna breed you, pretty,” Steve repeats, speaking into Bucky’s neck. “Fill you with my come til’ it’s leakin’ out of you, Buck, gonna fill you so full.”

His jaw throbs and aches, needing something to bite down on. Steve tightens his teeth over Bucky’s bond mark, digging them in deep enough to leave purple bruises on his skin. He growls as his hips continue to snap forward, Bucky’s tight, slick channel creating the friction that he craves. His climax is rapidly approaching, building at the base of his cock. His balls are drawn up tight to his body, filled with seed and aching to be emptied.

“Gon’ look so good carrying my pups, Buck, so full –  _fuck_ ,” Steve hisses, his words muffled by Bucky’s skin. His movements are pulling pained little whimpers from his Omega’s throat. Steve fumbles a hand between them, his fist closing around Bucky’s cock, which never really went soft after his first orgasm. 

Bucky yelps in surprise, thrashing madly in Steve’s grip, trying to get away from the tight clutch of Steve’s fist. Steve growls and bites down harder on Bucky’s neck, holding on until Bucky’s struggles subside. His fist is slick with Bucky’s come, making it easy for him to glide it over Bucky’s dick, bringing it to full hardness. Steve jerks him off at a pace that is slightly faster than his thrusting, quickly bringing Bucky to the brink of orgasm, needing to feel his Omega come on his knot.

Bucky’s fingers are scratching up Steve’s back, scrabbling for purchase on Steve’s flexing, rippling muscles. He moans and whines and whimpers, making unintelligible, incoherent noises as the pleasure builds. Steve is mindless with need and desire, the urge to fuck and bite and claim crowding out all other thoughts in his mind. Primal grunting and growling fills the air between them, neither of them capable of stringing together coherent sentences. They’ve both given in to their animalistic urges, following their biology, their desire to fuck, couple,  _mate_.

“Alpha— _oh_ , m’god,  _Alpha_ ,” Bucky cries out, muscles suddenly going taut as wetness spills over Steve’s hand. Bucky’s scent soars, his satisfaction and pleasure filling Steve’s nose.

 _That_ is what ultimately pushes Steve over the edge.

His knot swells even further as the contents of his balls are emptied into Bucky’s channel. Steve comes with a feral growl, his rut-brain proud to have achieved its aim of breeding his perfect Omega. His knot is stuffing Bucky full, filling his hole to bursting – its presence ensures that no one else can claim what’s his. Only Steve is allowed to have this.

Steve’s brain whites out as his orgasm rushes through him, ecstasy pumping through his veins. The ache in his jaw, his knot and his groin have diminished, their insistent fire replaced by a satisfied buzz. He can feel the rapid contractions of Bucky’s lock around his knot, milking his cock dry, his hole and womb greedy for all the seed that Steve has to offer.

His knot will keep his seed trapped inside Bucky, ensuring that Steve breeds his pretty Omega, filling him up with a litter of pups. Steve growls possessively at the thought, his tongue darting out to taste Bucky’s skin that is still caught between his teeth. He’s vaguely aware of his hips grinding restlessly against Bucky’s ass, pulling quiet moans from Bucky’s mouth.

Rationally, Steve knows that Bucky’s on a very good brand of birth control and that the chances of Steve knocking him up outside of a heat are pretty minimal, anyway. His Alpha hind-brain, however, cares fuck-all about that. Right now, what matters is that his Omega has submitted so sweetly to him and has given Steve the privilege of tying them together. Bucky’s taken his knot perfectly, has allowed Steve to fill his channel to bursting with a flood of seed, breeding his fertile womb.

As the haze of afterglow descends upon him, Steve uses the last of his strength to heave himself onto his back, being careful to not jostle Bucky around too much. The knot pulls at his Omega’s stretched hole, making him whine and mewl. They’ll rest for a bit and catch their breaths, gathering up the energy that they’ll both need to handle the next wave of Steve’s rut.

**Author's Note:**

> reblog this on [tumblr!](https://a-splash-of-stucky.tumblr.com/post/175529432810/fill-me-with-your-love/)


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